In areas where there is pedestrian and vehicular traffic, particularly in publicly-accessible areas, it is common to have specific pedestrian pathways, such as walkways. Such walkways might include sidewalks, pedestrian or vehicular bridges, pedestrian and vehicle ramps, paved walkways through parks, patios, floor surfaces, balconies and the like. Such pedestrian walkways exist in public transit facilities (e.g., subway stations), light rapid transit, bus rapid transit, railway stations, and other locations where there is pedestrian traffic. In many types of pedestrian walkways, there is a requirement for pedestrians to be able to safely navigate such walkways and to remain on the walkways, especially where public transit vehicles are passing closely by. This is particularly important for mass transit platforms near, for example, subways, buses, or trains where there is a need for safe pedestrian walkways.
Besides specific pathways for pedestrians, there can be a need for pedestrians to be able to maintain good traction on pedestrian walkways in order to prevent slips and falls, particularly on outdoor surfaces that can be subject to inclement weather such as wind, rain, snow, or ice.
Additionally, it may be important for pedestrians to be able to determine the presence of platform edges so that the pedestrians do not accidentally walk off the edge of a platform, especially if a vehicle might be passing by. This may be especially important in mass transit situations, and particularly for subways or commuter trains, where the side of the subway or train is right at the edge of the platform. The need for making the presence of platform edges easy to determine may be of particular importance when making such facilities accessible and safe for blind or visually impaired persons.
Conventional concrete and wooden transit platforms may have a durability problem due to degradation by environmental chemicals such as salt, urea, acid rain, oils, and greases as well as stray electrical currents. This necessitates regular maintenance and periodic replacement of the platforms at considerable cost and service disruption to transit authorities. Steel and concrete are also susceptible to corrosive elements, such as water, salt water, and agents present in the environment like acid rain, road salts, or chemicals. Environmental exposure of concrete structures leads to pitting and spalling in concrete and thereby results in severe cracking and a significant decrease in strength in the concrete structure. Steel is likewise susceptible to corrosion, such as rust, by chemical attack. The rusting of steel weakens the steel, transferring tensile load to the concrete, thereby cracking the structure. The rusting of steel in standalone applications requires ongoing maintenance, and after a period of time corrosion can result in failure of the structure. The planned life of steel structures is likewise reduced by rust. Wood has been another long-time building material for bridges and other structures. Wood, like concrete and steel, is also susceptible to environmental attack, especially by rot from weather and termites. In such environments, wood encounters a drastic reduction in strength which compromises the integrity of the structure. Moreover, wood undergoes accelerated deterioration in structures in marine environments, and is susceptible to fire damage.
Concrete structures are typically constructed with the concrete poured in situ as well as using some preformed components pre-cast into structural components (e.g., supports) and transported to the site of the construction. Constructing such concrete structures in situ requires hauling building materials and heavy equipment and pouring and casting the components on site. This process often requires the use of cranes, which can be costly and difficult to use in the case of nearby overhead wires. The weight of concrete structures also increase the necessary foundational requirements, which can increase cost, complexity and time of construction. Consequently, this process of construction involves lengthy construction times and is generally costly, time consuming, subject to delay due to weather and environmental conditions, and disruptive to existing traffic patterns.
Pre-cast concrete structural components are extremely heavy and bulky. Therefore, these are typically costly and difficult to transport to the site of construction due in part to their bulkiness and heavy weight. Although construction time is shortened as compared to poured in situ, extensive time, with resulting delays, is still a factor. Construction with such pre-cast forms is particularly difficult, if not impossible, in areas with difficult access or where the working area is severely restricted due to adjoining tracks, buildings, or platforms. In typical pre-cast concrete construction, tolerances of plus or minus one-quarter inch or more are common, making precise installation and alignment difficult. Pre-cast components may also require the addition of a topping surface to create a finished, level surface.
There is a need for a lightweight structure to facilitate installation in areas with difficult access and/or restricted working areas. In addition, a lightweight structure eliminates the costly concrete foundations and steel support systems necessary to support conventional concrete platforms.
Therefore, an improved modular assembly, such as for a transit platform, is needed.